Poly(arylene ether sulfone ketone)s containing densely piperidinium-functionalized carbazole derivatives as anion exchange membranes with improved ionic conductivity and alkaline stability

Carbazole and its derivatives have recently shown considerable potential for application in anion exchange membranes (AEMs), yet only a few studies have been reported so far. Herein, a carbazole derivative with multiple phenyls was synthesized, which was copolymerized into the polymer backbone, subsequently by densely piperidinium-functionalized, yielding a series of copolymers named PIP-PAESK-Cz-x as AEMs. The prepared membranes indicated well-defined microscopic morphology due to the drastic polarity contrast between the hydrophilic units and hydrophobic polymer backbone. Furthermore, compared with another analogous AEM, the presence of rigid carbazole significantly improved the water adsorption and alleviated the aggressiveness of OH− for PIP-PAESK-Cz-x. Consequently, the PIP-PAESK-Cz-25 membrane demonstrated decent hydroxide conductivity of 61.5 mS cm-1 at 80 oC, and stable performance upon treatment with harsh alkaline environments at 30 oC or 60 oC. In addition, a maximum power density of 407.8 mW cm-2 in the H2/O2 fuel cell was also achieved. This work presented a novel strategy to exploit the carbazole, which is expected to provide additional ideas for more carbazole-based AEMs in the future.